• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

Tool Post Grinder

If I was to make a holder, it would be exactly like the Aloris #4D, boring bar holder with split clamping.
 
trlvn said:
Unless you plan to do grinding a LOT, I wouldn't bother mounting it via the quick change tool post. It looks like it would be easy to make a new tee-nut and bracket such that you would take the QCTP off and mount the tool post grinder in its place.

Craig
Click to expand...

Yes, I considered that. But notice how the spindle motor is already very close to the lathe center.

To get some adjustment range, and still have the motor rigidly held, I had planned to hang the motor over the end of the compound taking advantage of the way a tool holder normally mounts.

I have some "glorious" plans for that grinder. They are probably all beyond its capability but a fellow must dream. If even 20% of those plans get realized, the grinder will see a lot of use. So I'd also really like to retain the quick change feature.
 
IMG_20220213_235552.jpg
IMG_20220213_235558.jpg

OK, done. Main issue i am seeing is that the collet wobbles at over 6000 rpm. But otherwise great. I have speed control and even on off switch.

You can see where I milled it thin. I hope now it's more clear.
 
TorontoBuilder said:
Is this the same 500 watt spindle as susquatch is using?

I was wondering what the TRO is with the er11 collet and if the larger spindle motors from vevor may be any better. I doubt it tho
Click to expand...

Yes it's 500w. Feels like plenty of power. I need to play around with the spindle assembly and see what results I get. The 12000 rpm speed will be good for small internal stones while I need to run much slower for 3in stones.
 
Tom Kitta said:
Yes it's 500w. Feels like plenty of power. I need to play around with the spindle assembly and see what results I get. The 12000 rpm speed will be good for small internal stones while I need to run much slower for 3in stones.
Click to expand...

That was my thinking too.

My spindle motor arrived a bit ago, but first I need to make a holder to fit my bxa quick change tool post. I already have an aluminium block to make it from. But I'm fussy so there is fair bit of planning and fabrication to do before I can actually run it.

Where do you get high quality (ie safe) well balanced 3" stones? And are they marked with a safe rpm for them?
 
TorontoBuilder said:
norton abrasives, toolroom wheels, still only ~5500 rpm for 3 inch wheel

My question is how are you mounting anything that size in a ER11 collet
Click to expand...

I haven't looked at the 3" wheel you referenced yet. But your question about ER11 collet is appropriate. I had assumed everyone was talking a 1/4" shaft designed to fit a motor with a 1/4" shaft holder of some kind. I was picturing a wheel somewhat like a cutoff blade just a bit thicker - say 1/4". But maybe I am not gunna be able to do outside grinding after all. Or perhaps only with a smaller stone held on an angle.

It's a good question. How would you answer it yourself?
 
Susquatch said:
My spindle motor arrived a bit ago, but first I need to make a holder to fit my bxa quick change tool post. I already have an aluminium block to make it from. But I'm fussy so there is fair bit of planning and fabrication to do before I can actually run it.
Click to expand...
Why don't you want to modifying the holder that came with the motor?
 
YYCHM said:
Why don't you want to modifying the holder that came with the motor?
Click to expand...

You have no idea how hard I tried to make that work. In the end, I simply gave up. The original doesn't have enough meat to take the dovetail and the through bolts end up interfering with the compound table. Lastly, a two part assembly would be difficult to assemble. An entirely new holder doesn't need bolts and can accommodate the dovetail.

The bigger question is can I make a dovetail that fits my tool post well enough to handle the spindle motor. ;)
 
Susquatch said:
You have no idea how hard I tried to make that work. In the end, I simply gave up. The original doesn't have enough meat to take the dovetail and the through bolts end up interfering with the compound table. Lastly, a two part assembly would be difficult to assemble. An entirely new holder doesn't need bolts and can accommodate the dovetail.

The bigger question is can I make a dovetail that fits my tool post well enough to handle the spindle motor. ;)
Click to expand...

I should show you my design. No issues - used original aluminium. Less work. Just make it square and add an adapter plate to the bottom. The whole thing is very rigid. It is held with 3/8 bolt against T-nut.

Basically I machined T-nut - simple - right?

I machined the original clamp square so its even. I measured how much higher it needs to be then my spindle - about 5.5mm. I machined adapter plate of 5.5mm. I added adapter plate to the bottom via 4 tiny cap screws - I think size 10-24. The 3/8 just holds the adapter plate against T-nut. Works great. Very rigid. Maybe I would not lift the whole lathe by it but I am sure it will work for the grind stones.
 
Susquatch said:
I haven't looked at the 3" wheel you referenced yet. But your question about ER11 collet is appropriate. I had assumed everyone was talking a 1/4" shaft designed to fit a motor with a 1/4" shaft holder of some kind. I was picturing a wheel somewhat like a cutoff blade just a bit thicker - say 1/4". But maybe I am not gunna be able to do outside grinding after all. Or perhaps only with a smaller stone held on an angle.

It's a good question. How would you answer it yourself?
Click to expand...

I got some cheap Chinese wheels and norton wheels.

I have these bad boys:
www.ebay.com

PACK OF 5 NEW!!! NORTON SG RECESSED GRINDING WHEELS 3" X 1-1/4" X 5/8" 5SG46-KVS | eBay

Recessed Grinding Wheels.
www.ebay.com

I also have like 10 cup wheels in case someone wants them - good stuff, norton as well. I don't think I need 10 identical ones. https://www.ebay.com/itm/353890612374

Not sure what is the RPM max. I assume 5500 or 6000 would be safe limit.
 
Tom, how is the ER collet holder attached to the shaft (like key or set screw on flat or?).
How are you varying RPM on that motor? I guess I'm more wondering what happens to 500W rating when you go to 40% throttle or whatever?
Do you happen to know what it has for bearings or just give it a go?
 
PeterT said:
I might take you up on cup wheel. I need to figure out adaptability to my bench grinder. Is 1.25 the hole ID I assume?
NORTON ALUNDUM CUP GRINDING WHEELS 4"/3" X 1-1/2" X 1-1/4"
Click to expand...

Yes, 1 1/4 is I think standard for SG. You can always use adapter - my TC&G is 1 in and I have some adapters to use same wheels as on SG.
 
PeterT said:
Tom, how is the ER collet holder attached to the shaft (like key or set screw on flat or?).
How are you varying RPM on that motor? I guess I'm more wondering what happens to 500W rating when you go to 40% throttle or whatever?
Do you happen to know what it has for bearings or just give it a go?
Click to expand...

Collet is attached via two set screws. Its a DC motor and you simply lower the voltage to get speed down. I do not think it will be a big deal, these grinders are usually not too powerful - I mean 6" pedestal grinders are usually 250w and they move two 6" stones doing far more cutting action then 3" or similar stone.
 
TorontoBuilder said:
AH. I see.

I'd heard that those ER11 chucks were impossible to remove from the shaft.

Did you buy or make a new er20 collet chuck? I may just buy a dedicated tool post grinder spindle
Click to expand...

Yes the ER11 chuck was like .1mm smaller then the spindle. Same with the ER20. I could not have put them on, it was not even close to interference fit. So I reamed 8mm. Not sure whatever that was a great idea - I guess I see soon.
 
You must log in or register to reply here.
Back
Top